Pump Selection for Rainwater Harvesting: Gravity-Fed Centrifugal Booster

1500-gal buried tank catching runoff. Gravity-fed inline pump for outdoor shower + faucet for 1-2 sprinklers on 30'x60' garden/lawn. Considering shallow well pump with 5-gal tank, 30-50 PSI range. Wants higher PSI for distance.

Pump Type Recommendation

Tony: "If you can install the pump below the surface of the water in the tank... then an end-suction centrifugal is the booster pump of choice... minimal priming... fewer friction losses."

Sizing Factors

Need flow (GPM) and head (pressure) requirements. Pump curves: X-axis = flow, Y-axis = feet of head (1 ft head = 0.433 PSI). Suggests 3/4 HP or 1 HP depending on distance.

Specific Models

• Grundfos MQ 3-45: 3/4 HP, built-in flow sensor and diaphragm, "plug & play." Link
• Berkeley (Sta-Rite): Also good for this application.

Gravity feed from tank = flooded suction = ideal for end-suction centrifugal. No pressure tank needed if pump has built-in pressure control (like Grundfos MQ).